I am trying to make a simple text editor using JTextArea, but when I type more text so that it goes off the screen, the JScrollPane is still not enabled and not letting me to scroll. I've looked for hours for answers on the internet but nothing seemed to help me.
Here is my code:
import mods.JFrame.JFrameMods;
import javax.swing.*;
public class NimbleIDE {
JFrame frame;
JTextArea main;
JScrollPane scroll = new JScrollPane(main);
NimbleIDE() {
frame = new JFrame();
main = new JTextArea();
frame.add(main);
//Frame setting up
initialiseBlankJFrame(frame, "NimbleIDE");
frame.add(scroll);
//Text setting up
main.setSize(JFrameMods.getScreenWidth() - 14, JFrameMods.getScreenHeight()); //JFrameMods is a custom class I made previously
main.setWrapStyleWord(true);
main.setLineWrap(true);
main.setEditable(true);
//Scroll setting up
scroll.setBounds(JFrameMods.getScreenWidth() - 14, 0, 16, JFrameMods.getScreenHeight() - 23);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
}
initialiseBlankJFrame(JFrame frame, String title) {
frame.setVisible(true);
frame.setExtendedState(MAXIMIZED_BOTH);
frame.setLayout(null);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.getContentPane().setBackground(Color.white);
frame.setTitle(title);
}
}
This:
JTextArea main;
JScrollPane scroll = new JScrollPane(main);
effectively means this:
JScrollPane scroll = new JScrollPane(null);
You're passing a null object to the JScrollPane.
You can fix your problem by passing an actual JTextArea object to your scroll pane. Also note that the scroll pane is the only component that you explicity have to add to your JFrame. Something like this:
public class NimbleIDE {
JFrame frame;
JTextArea main;
JScrollPane scroll;
NimbleIDE() {
frame = new JFrame();
main = new JTextArea();
scroll = new JScrollPane(main);
//Frame setting up
initialiseBlankJFrame(frame, "NimbleIDE");
frame.add(scroll);
// ...
}
// ...
}
You may also want to take a look at the following Java Trails:
How to Use Scroll Panes (The Java™ Tutorials > Creating a GUI With Swing > Using Swing Components)
Doing Without a Layout Manager (Absolute Positioning) (The Java™ Tutorials > Creating a GUI With Swing > Laying Out Components Within a Container)
Related
Anyone help me how to add a scroll bar to a JTextArea with Swing in Java?
The JTextArea just disappear when I add the scroll bar on it.
Hope somebody get me add a vertical scrollbar on it.
Additional explanation will be very thankful
public class Practice extends JFrame {
JFrame frame = new JFrame("AAA");
JTextArea textarea = new JTextArea();
JScrollPane scroll = new JScrollPane(textarea);
JPanel panelForScroll = new JPanel(null);
public Practice(){
frame.setLayout(null);
frame.setBounds(100,100,400,710);
frame.setResizable(false);
frame.setVisible(true);
textarea.setEditable(false);
textarea.setFont(new Font("arian", Font.BOLD, 16));
textarea.setBounds(20, 280, 340, 70);
panelForScroll.add(scroll);
frame.add(panelForScroll); //can't find text area....
}
public static void main(String[] args) {
new Practice();
}
}
There are several errors in your code:
You're using a null layout, this is discouraged as it produces more problems than solutions, specially when you try to use JScrollPanes, since they take the preferredSize of the Component to decide whether to add the scroll bars or not. See Why is it frowned upon to use a null layout in Swing? for more information about this. To fix this, remove this line:
frame.setLayout(null);
And instead use a layout manager or combinations of them along with borders for extra spacing between components.
While null layouts might seem like the best, easiest and faster way to design complex GUIs for Swing newbies, the more you progress in it, the more problems related to the use of them you'll find (as it's the case)
You're extending your class from JFrame and you're creating an instance of JFrame in it too, please use one or the other. When you extend JFrame you're saying your class is a JFrame and thus it cannot be placed inside another Container because JFrame is a rigid container. I recommend to forget the extends JFrame part, since anyway you're not using the JFrame that is generated by this action and stay with the object you created. See https://stackoverflow.com/questions/41252329/java-swing-using-extends-jframe-vs-calling-it-inside-of-class for a more detailed answer about this problem.
You're making your GUI visible before you have added all the elements, this could cause your GUI to not display all the elements until you hover over them, this line:
frame.setVisible(true);
Should be one of the last lines in your program
You're not placing your program on the Event Dispatch Thread (EDT) which makes your application to not be thread safe, you can fix it by writing this on your main method.
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
//Place your constructor here
}
});
You're setting bounds for the textArea but not for the scrollPane, but you should really not be setting the bounds manually (see point #1 again).
Now, you can make a simple GUI with a JTextArea with a JScrollPane as follows:
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class ScrollPaneToTextArea {
private JTextArea textArea;
private JFrame frame;
private JScrollPane scroll;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ScrollPaneToTextArea().createAndShowGui();
}
});
}
public void createAndShowGui() {
frame = new JFrame("ScrollPane to TextArea");
textArea = new JTextArea(10, 20); //Rows and cols to be displayed
scroll = new JScrollPane(textArea);
// scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
frame.add(scroll); //We add the scroll, since the scroll already contains the textArea
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Which produces this output and the scroll bars are added when needed (i.e. when text goes further than the rows it can handle in the view)
If you want the vertical scroll bars to appear always you can uncomment the line:
scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
Which will produce the following outputs:
You can read more about JScrollPane in the docs and JTextArea also in their own docs.
JPanel panelForScroll = new JPanel(null);
This sets the NULL Layout to this JPanel. This would require more configuration (just as you did for the frame object).
Just remove the null (also from frame.setLayout(null)!)
You have to use Jtextpane to get the scroll bar on textarea.
JTextArea ta = new JTextArea();
JScrollPane sp = new JScrollPane(ta);
JFrame f = new JFrame();
f.getContentPane().add(sp);
you are setting the panel's layout to null,then you didn't specify the scroll bar bounds. Since you only have one component in your panel which is the scroll bar I recommend using FlowLayout
I am trying to add JScrollPane to my large JTextArea, but whenever I include the JScrollPane code, my whole JTextArea disappears.
public myGUI() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 1174, 656);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
contentPane.setVisible(true);
JTextArea textArea_1 = new JTextArea();
textArea_1.setBounds(203, 5, 869, 440);
textArea_1.setEditable(true);
textArea_1.setVisible(true);
contentPane.add(textArea_1);
JScrollPane scroll = new JScrollPane (textArea_1);
scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
contentPane.add(scroll);
}
Several problems with your code:
You're trying to add a component, here your JTextArea called textArea_1, to multiple containers, here the contentPane and the JScrollPane. You can't do this in Swing as a component can be added to only one component. Add it only to the JScrollPane and not to the contentPane, and then add the scroll pane to the GUI.
You're constraining the size of your JTextArea via setBounds which almost guarantees that the JScrollPane will not work since doing this prevents the JTextArea from expanding when it holds more text than is shown. Instead set the JScrollPane's rows and columns properties and not its bounds. This will be the number of rows and columns that it should display within the scrollpane
You're using null layouts but not specifying the size of the JScrollPane, and so it defaults to a size of [0, 0] -- and this is why your JTextArea disappears. Null layouts require complete specification of all component sizes and positions.
You're using null layouts to set up your GUI. While null layouts and setBounds() might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
For example:
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import javax.swing.*;
#SuppressWarnings("serial")
public class MyGuiPanel extends JPanel {
// some row and column values for our JTextArea
private static final int TXT_AREA_ROWS = 25;
private static final int TXT_AREA_COLS = 80;
// create the JTextArea, passing in the rows and columns values
private JTextArea textArea = new JTextArea(TXT_AREA_ROWS, TXT_AREA_COLS);
public MyGuiPanel() {
// create the JScrollPane, adding our JTextArea
JScrollPane scroll = new JScrollPane(textArea);
scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
// lets add some buttons to the bottom of the GUI just for fun
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, 5, 0));
buttonPanel.add(new JButton("Save"));
buttonPanel.add(new JButton("Open"));
buttonPanel.add(new JButton("Delete"));
buttonPanel.add(new JButton("Exit"));
// let's add a title to the top:
JLabel title = new JLabel("This is my Applications's Title", SwingConstants.CENTER);
title.setFont(title.getFont().deriveFont(Font.BOLD, 24)); // and make
// the text
// *BIG*
// use a BorderLayout for our GUI
setLayout(new BorderLayout(5, 5));
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
add(scroll, BorderLayout.CENTER); // add the scrollpane to the center
add(buttonPanel, BorderLayout.PAGE_END); // the button panel to the
// bottom
add(title, BorderLayout.PAGE_START); // and the title JLabel to the top
}
private static void createAndShowGui() {
// create our GUI JPanel
MyGuiPanel mainPanel = new MyGuiPanel();
// create a JFrame to add it to
JFrame frame = new JFrame("My GUI");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel); // add the GUI to the JFrame
frame.pack(); // tell the layout managers to do their work
frame.setLocationByPlatform(true);
frame.setVisible(true); // display the GUI
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
Also, if your program extends JFrame, understand that you are painting yourself in a corner by doing this, forcing you to create and display JFrames, when often more flexibility is called for. In fact, I would venture that most of the Swing GUI code that I've created and that I've seen does not extend JFrame, and in fact it is rare that you'll ever want to do this. More commonly your GUI classes will be geared towards creating JPanels, which can then be placed into JFrames or JDialogs, or JTabbedPanes, or swapped via CardLayouts, wherever needed. This will greatly increase the flexibility of your GUI coding.
You do not need setBounds for your JTextArea. Because you are using a null layout and the JScrollPane has no bounds, nothing shows up. Your JTextArea is also added to two places which would cause some problems. I would recommend any of swings layout managers. As an example using BorderLayout which is one of the easiest managers:
public mygui() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
setSize(700, 500);
setLayout(new BorderLayout());
JTextArea textArea_1 = new JTextArea();
textArea_1.setEditable(true);
JScrollPane scroll = new JScrollPane(textArea_1);
scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
add(scroll, BorderLayout.CENTER);
}
I have a JPanel which dynamically allocates buttons in a vertical layout. The problem is when I place this panel inside JScrollPane, the scrollPane appears vertically above my buttons. I'm not sure why this is happening. Here's the code:
public static void GUI ()
{
JFrame frame = new JFrame(GAME_TITLE);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(400,600));
frame.setLayout(new GridLayout(0,1));
Menu theMenu = new Menu();
theMenu.setLayout(new GridLayout(mSize,0));
theMenu.setOpaque(true);
JScrollPane scroll = new JScrollPane(theMenu,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
frame.add(scroll);
theMenu.createGameButtons(frame);
frame.pack();
frame.setVisible(true);
}
I've tried quite a few things with no success. Also, I'm attaching a link to a screen shot
Christian Hujer answered the question with:
The bug is in the code that is not visible. The bug is in the method createGameButtons. There, the buttons are created and added to the frame instead of adding them to the Menu itself (which I guess is a subclass of JPanel)
I am a java beginner and I want to make a simple text editor but I find the following problem. The JTextArea doesn't re-size along with the JFrame. Here is my code :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class textEditor
{
JFrame frame;
JTextArea textArea;
JScrollPane scrollPane;
//JButton button;
public textEditor() //Constructor
{
frame = new JFrame("Title of the frame!");
frame.setLayout(new FlowLayout());
textArea = new JTextArea("");
scrollPane = new JScrollPane(textArea);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
//button = new JButton();
}
public void launchFrame()
{
//Adding Text Area and ScrollPane to the Frame
frame.getContentPane().add(textArea);
frame.getContentPane().add(scrollPane);
//Make the Close button to close the frame when clicked
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Displaying the Frame
frame.setVisible(true);
frame.pack();
}
public static void main(String args[])
{
textEditor window=new textEditor();
window.launchFrame();
}
}
Please don't forget that I'm a beginner so please give me a solution in simple words.
The JTextArea doesn't re-size along with the JFrame as you are using a FlowLayout manager which uses preferred sizes of components instead of expanding them to fill the full space of the container. To fix you can remove the line:
frame.setLayout(new FlowLayout());
JFrame containers use BorderLayout manager by default, which will do the necessary sizing that you are looking for.
Also remove the line
frame.getContentPane().add(textArea);
as only the JScrollPane is required to be added to the frame.
I am developing a small desktop application in NetBeans. On my UI, I place a JPanel and put a single JLabel on it. The content of this JLabel is generated dynamically, so if the content is very large then it goes out of screen.So is there any way in which I can specify a fixed size for the JPanel and of course ScrollBars should appear when the text exceeds the screen size.
You will have to just pass Component reference to the JScrollPane Constructor.
It will work fine. You can definetely use JScrollPane
The following is the sudo example of the JScrollPane for JPanel from my past project. Hope it will be useful for you.
import javax.swing.*;
import java.awt.*;
public class Frame01
{
public static void main(String[] args){
SwingUtilities.invokeLater (new Runnable ()
{
public void run ()
{
JFrame frame = new JFrame("panel demo");
frame.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
JPanel panel = new JPanel();
Container c = frame.getContentPane();
panel.setSize(100,100);
panel.setLayout(new GridLayout(1000,1));
for(int i = 0; i<1000;i++)
panel.add(new JLabel("JLabel "+i));
JScrollPane jsp = new JScrollPane(panel);
c.add(jsp);
frame.setSize(100,100);
frame.setVisible(true);
}
});
}
}
Use JScrollPane to contain Your big JPanel.
so in case when the contents are very large it goes out of screen, maybe you have to look for TextComponents as JTextArea or JEditorPane, tutorial contains example including basic usage for JScrollPane
In the Navigator, click on JPanel with the right mouse button --> Enclose In --> Scroll Pane.
Done!, You have now scrolls